Foregut choristoma of the ileum, (adenomyoma)--a case report.

An ileal adenomyoma in a 7-year-old boy who presented with jejunoileal intussusception is described and the term "foregut choristoma" is proposed for this and related conditions, such as ectopic pancreas or heterotopic Brunner's glands in the gastrointestinal tract. The polypoid mass in the ileum of this patient was composed of cystically dilated glandular structures lined by a tall columnar epithelium resembling hepatobiliary or pancreatic ductal epithelium, hypertrophic and irregular smooth muscle bundles surrounding the glandular elements, and small amount of fibrous stroma. Reported cases of this disorder in the gastrointestinal tract are generally confined to the antrum of the stomach.